I wouldn't think it's contaminated seed because cabbage seed is tiny tiny and squash seed is big, you'd notice the difference, but why did it volunteer there?Yes, @Sheal that could well be. A marrow, as I understand is a courgette/zucchini that has been left to fully mature.
I have never grown marrow per se, but many many zucchinis. It looks more like yellow squash to me, however. Time will tell and it shouldn't be long.
Seems very interesting that @Gary and I, separated by 1000 miles would see the same in cabbage seeds. Makes me think the seed supplier has contaminated seed. Suppliers seed can go into many different brands/packages.
Either someone threw out a fruit or seed was planted earlier (most likely this spring) but refused to germinate until now
Odd how it followed garys row, so my guess planted
Good news is squash leaves are edible


